RS232 Connection
Early barcode scanners, of all formats, almost universally used the then-common RS-232 serial interface. RS232 output scanners also normally require an AC adapter to supply power to the scanner because the RS232 port cannot supply enough power to run a barcode scanner.
* Related product for RS232 Barcode Scanners: https://www.marsonscan.com/products/Fixed_Mount_Scanners/